Patterning abnormalities in the early neural plate. Expression of genes involved in patterning the early neural plate visualized by whole-mount in situ hybridization for dlx3 (A,B; 20x) and otx2 (C,D; 20x) at late gastrulation stages (90% epiboly). Wild-type (A) and mutant (B) embryos indicate the lack of the anterior-medial domain of dlx3 (arrow) in nrd. In these embryos, anterior is to the top, dorsal to the right. (C,D) Anterior view of otx2 expression in wild type (C) and nrd (D): at the border region of the neural plate otx2 expression level is reduced (arrow) but appears to extend in a pattern of normal shape in mutant embryos. In C and D, the anterior edge of the neural plate is to the top, with a dorsal and posterior neural plate toward the bottom. Schematic diagrams illustrate the normal expression domains of dlx3 in the neural crest and placodal domain, between the neural and nonneural ectoderm, otx2 in the neural plate, and GATA3 in the non-neural ectoderm in wild-type embryos. GATA3 expression is not affected in nrd embryos (not shown).
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